1 // SPDX-License-Identifier: (GPL-2.0+ OR MIT)
2 /*
3 * Copyright 2022 Gateworks Corporation
4 *
5 * GW72xx RS422 (RS485 full duplex):
6 * - GPIO1_0 rs485_term selects on-chip termi
7 * - GPIO4_0 rs485_en needs to be driven high
8 * - GPIO4_2 rs485_hd needs to be driven low
9 * - UART4_TX is DE for RS485 transmitter
10 * - RS485_EN needs to be pulled high
11 * - RS485_HALF needs to be low
12 */
13
14 #include <dt-bindings/gpio/gpio.h>
15
16 #include "imx8mm-pinfunc.h"
17
18 /dts-v1/;
19 /plugin/;
20
21 &gpio4 {
22 rs485-en-hog {
23 gpio-hog;
24 gpios = <0 GPIO_ACTIVE_HIGH>;
25 output-high;
26 line-name = "rs485_en";
27 };
28
29 rs485-hd-hog {
30 gpio-hog;
31 gpios = <2 GPIO_ACTIVE_HIGH>;
32 output-low;
33 line-name = "rs485_hd";
34 };
35 };
36
37 &uart2 {
38 pinctrl-names = "default";
39 pinctrl-0 = <&pinctrl_uart2>;
40 rts-gpios = <&gpio5 29 GPIO_ACTIVE_HIG
41 linux,rs485-enabled-at-boot-time;
42 status = "okay";
43 };
44
45 &uart4 {
46 status = "disabled";
47 };
48
49 &iomuxc {
50 pinctrl_uart2: uart2grp {
51 fsl,pins = <
52 MX8MM_IOMUXC_UART2_RXD
53 MX8MM_IOMUXC_UART2_TXD
54 MX8MM_IOMUXC_UART4_TXD
55 >;
56 };
57 };
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